A civil union is a legally recognized relationship between members of a same-sex couple, with rights similar to those of a marriage relationship.
As of my knowledge cutoff in 2023, Ohio does not recognize civil unions. The state only recognizes marriage, which is legally defined as a union between two people regardless of their sex, following the U.S. Supreme Court's decision in Obergefell v. Hodges in 2015. This landmark ruling legalized same-sex marriage across all states, rendering the need for a separate civil union status for same-sex couples largely moot. Therefore, in Ohio, same-sex couples have the same right to marry as opposite-sex couples, and with marriage, they gain all the state and federal benefits, protections, and responsibilities that the institution provides.